Blow a Bubble with Your Hands
Re-open your finger into the "OK" position, there should be a thin layer of soap, looking like it does on a bubble wand, inside that space (be sure, when opening your fingers not to disconnect from the thumb or you will need to start all over).
Put your hand in the "OK" position and close your index finger into your thumb, so you're making a fist with just your thumb and index finger.